This invention relates to a mobile loudspeaker system.
A conventional loudspeaker system that is installed on an automobile door is shown in FIG. 7. There, an input signal in is applied through a filter consisting of an inductance element L1 and a capacitor C1 to a woofer 1. The input signal also is applied through a filter consisting of an inductance element L2 and a capacitor C2 to a tweeter 2.
The circuit of the woofer 1 is adapted to reproduce middle and low frequency signals; accordingly, the input signal is high-cut with -12 dB/oct (or -6 dB/oct) above a given frequency. The circuit of the tweeter 2 is adapted to reproduce high frequency signals and the input is high-passed with 12 dB/oct (or 6 dB/oct) below a given frequency.
However, if such loudspeaker system, having an output frequency response that is flat, is installed on a vehicle door or doors, as is shown in FIG. 8 the frequency characteristic of the sound pressure inside the vehicle shows a peak in a frequency range of from 1.5 KHz to 3 KHz. For listening comfort, it is desirable to have a flat sound pressure characteristic across the entire frequency range.